| Case Name |
Explosion due to temperature rise from careless handling in the nitrosation reaction |
| Pictograph |
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| Date |
November 5, 1962 |
| Place |
Ube, Yamaguchi, Japan |
| Location |
Laboratory |
| Overview |
In the experiment on the nitrosation of benzoic acid, an explosion occurred because the temperature was raised too high for the improvement in the yield, and two persons got injured. Thermal hazard of the used reagent was confirmed in the study of safety beforehand. However, an injury accident happened because thermal instability of the mixture had not understood and enough protection in case of emergency has not been prepared. |
| Incident |
An explosion occurred under experiment on the nitrosation of benzoic acid in the laboratory of the factory, and two persons got injured. |
| Processing |
Research and development |
| Process Flow |
Fig3.Unit process flow
|
| Chemical Reaction |
Nitrosation |
| Chemical Equation |
Fig2.Chemical reaction formula
|
| Substance |
Benzoic acid, Fig4 |
| Nitrosyl perchlorate, Fig5 |
| Perchloric acid, Fig6 |
| Type of Accident |
Explosion |
| Sequence |
4.1g of benzoic acid, 3.8g of perchloric nitrosyl, and 15g of 70% perchloric acid aqueous solution were mixed. An explosion occurred while temperature rose up to 98-99 °C with stirring. |
| Cause |
An explosion occurred because the temperature was raised too high for improving the yield. A sufficient yield was not obtained when it was raised up to 90 °C in the last experiment, so the next experiment was conducted at higher temperature to raise the yield. It had been confirmed that the reagent used for the experiment was comparatively stable below 100 °C, in case existing separately. However, it was not confirmed beforehand that the mixture decomposed exothermally at about 100 °C and generated carbon dioxide. |
| Countermeasures |
1. Safety education and training are carried out to the experiment staff beforehand.
2. The facilities which protect the experiment staff are prepared. |
| Knowledge Comment |
1. As unknown matters are tried in the experiment, previous safety study on operation is necessary.
2. Unexpected reactions sometimes occur especially in the experiment on the chemical reaction. Therefore, the facilities that protect the experiment staff must be prepared.
3. Even stable chemicals in case existing separately, it might become unstable if it is mixed with other materials. |
| Background |
1. Insufficient study of hazard factors before the experiment.
2. There were the defects of protection facilities for the experiment staff. |
| Reason for Adding to DB |
Example of accident caused dueto insufficient investigationon safety of the experiment |
| Scenario |
| Primary Scenario
|
Insufficient Analysis or Research, Insufficient Prior Research, No Check of Thermal Stability, Carelessness, Insufficient Understanding, Insufficient Recognition of Risk, Poor Value Perception, Poor Safety Awareness, Insuficient Education/Training for Safety, Nitrosation Reaction, Malicious Act, Rule Violation, Safety Rule Violation, Non-Regular Action, Change, Temperature Rise, Bad Event, Chemical Phenomenon, Unexpected Reaction, Secondary Damage, External Damage, Explosion, Bodily Harm, Injury, 2 person injured
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| Sources |
Masamitsu Tamura, Masahide Wakakura, Explosion under nitrosation reaction, Reaction danger -Accident case and analysis -, p.86(1995).
|
| Number of Injuries |
2 |
| Financial Cost |
¥ 2,550 |
| Multimedia Files |
Fig4.Chemical formula
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Fig5.Chemical formula
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Fig6.Chemical formula
|
| Field |
Chemicals and Plants
|
| Author |
OGAWA, Terushige (Graduate School of Environment and Information Sciences, Yokohama National University)
TAMURA, Masamitsu (Center for Risk Management and Safety Sciences, Yokohama National University)
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